The sword, variously described as a short sword, longsword, or greatsword, was crafted by Vecna. The blade is said to have been magically honed to a razor's edge, enhanced the wielder's strength, and could be used to call down lightning bolts from any storm clouds that might be overhead. The sword itself is intelligent, possessing a vile and murderous spirit.

The Sword of Kas first appeared in the Original D&D supplement, Eldritich Wizardry[1]. It was one of the first artifacts detailed for the Dungeons & Dragons game[2]. The sword has been updated many times[3] and has even been the object of quests as in the adventure Vecna Lives[4].